Virus... to test or not to test?
 

This month's AOS' Orchids magazine features an article by Sue Bottom in which a quick tour of her greenhouse with Dave Off (Waldor Orchids), to identify potentially virused orchids, turns into an orchid massacre.

This got me thinking... is it worth it? Should one test every orchid they receive and go through refunds and exchanges of virused orchids... if so... how many nurseries are really virus free anyway? And what's the worst that can happen? Shouldn't a vigorous plant be able to overcome infection?

Regarding ethics, I would never sell or gift a virused plant. But... for a private collection (of, yeah, a few dozen orchids), is it really worth it?

IMO, unless you're disseminating plant material, it probably doesn't matter that much. We all want virus free plants, but most living things are full of parasites, it's life.
I know of an extensive commercial plant collection that is (rumored) to be extremely virii filed. While by my own thoughts it doesn't make much difference, I've shied from ordering from there (so maybe it makes a little difference).

As I’ve stated many times, I believe that plants, like humans, carry every pathogen they have been exposed to, but that, unless an additional stress is plced on them, they can live on fine without issue. The corollary to that being that I doubt there is such a thing as a virus-free plant. “Undetectable”, sure. “Totally free of virus”, naaahhhh. That does not mean we should ignore them.

At this point, we are all carrying a strain or two of the coronavirus. That does not mean we will contaminate others on the bus. Display symptoms, on the other hand, and your viral loading has exploded, making the spread far more likely. Might it not be that way with plant pathogens, as well?

Back when I was selling plants, I purchased-for-resale a bunch of really spectacular Oncidiinae clones from a well-known commercial grower in Hawaii. A customer of mine tested and found it virused.

I contacted the vendor and they immediately refunded my money, as I did for anyone who got one through me, and destroyed the plants. The vendor, however, continued listing the plant. When I asked about that, the response was “most of them will just be sold locally to folks who will tie them to their fences.”

That seemed might irresponsible tome, so I stopped buying from them.

There are only 2 viruses today that we can identify ourselves with kits- -Cym MV & ORSV .I do NOT agree with Ray. Plant either got them or is free of them. If a planet is infected it can contaminate your whole orchids population.
For me main question is 'how old/dear/expensive/replaceable' are your plants. Are you ready to invest 5-10$ for testing each one of them ?
By the way -I buy 75% of my orchids from Dave. I think that he checks most of his valuable plants.

I don't worry about viruses in my orchid collection and I don't think it is worth testing a personal collection, but different strokes for different folks. I agree with Ray that most plants have some type of virus, and most all viruses that affect plants will be dormant if the plant is having its needs met. I have a fig collection and many people are worried about FMV, but as soon as the plants are mature FMV goes dormant and no longer effects the plant.

I grow in my basement and don't really have vectors / practice good greenhouse hygiene, so not too worried about spread.

I have not seen a single person on this board or in the FB groups I am in lose a collection to a virus. I would only think about this topic if I ran a commercial operation.

As a hobby grower that isn’t shelling out big bucks for any one plant, and isn’t collecting any hard to get plants, I don’t bother testing. I use good hygiene and sanitation practices to minimize transmission potential. But, if someone offered me a free plant that had tested positive for a virus I’d probably decline. I’d maybe take it if it could grow outside year round, but only if I liked it quite a bit.

Why would you decline ?? Seems like you have "good hygiene and sanitation practices" In any case your collection does not include "big buck" or "hard to get plants" ,so why not add a nice free plant to the collection ?

Having good hygiene practices doesn’t mean I want to intentionally bring in plants with viruses. I can’t easily know if a plant I’m buying is virus-free before I buy it, so I take necessary precautions to account for that risk (buy from quality vendors, minimize contamination, etc.). If I know a plant has a virus, I can very easily avoid the known risk.

I believe a commercial seller should test every plant.

Do I test mine? No way. I don't sell plants commercially and if someone asks for a division of one of mine and asks if it's been tested I respond "nope, take it or leave it"

That being said, I've been known to sacrifice a couple of plants that looked wrong to me.

I'm with Ray here. The core issue is that there are more unknowns than knowns. For example, in terms of undetectable levels of a virus. A person with HIV who takes their medication as prescribed might keep their infection undetectable and untransmittable and live a long and otherwise healthy life. On the other hand, a person not receiving such treatment may develop AIDS within a couple of years and pass away shortly after. Extreme opposite outcomes. The key here is that to keep HIV at bay or other viruses such as Hepatitis C, medication is needed as our immune system does not protect us from them.

On the other hand, less pathogenic viruses, such as the flu, seasonal coronaviruses, or the omnipresent coronavirus causing Covid-19, can be fought by our immune systems.

The question is whether the viruses infect orchids more like HIV or the Flu... And how are they transmitted? Carried in shared water? Proximity?

And can we pump their immune systems by providing the appropriate light, temperature, nutrition, and microbiological support?

It's fair to try to control your collection so as to not be suddenly forced to throw away 20 years of work. But isn't that why we generally stretch ourselves by buying more orchids? Because we accept that a good bunch of those will die and that space will be freed up.

Maybe the solution should be to have plants in "islands" instead of growing together and having an island for the "sus" plants... But by the time they're sus... would that be too late? Who knows.

Different virus may or may not be transmitted by water droplets, hands, knives, clippers, mealy bugs, scale, aphids... and touching one plant to another. Smokers have tobacco mosaic virus on their hands (and in their lungs) and TMV does infect orchids.

A poorly growing plant might or might not have virus infection. A vigorous plant might or might not have virus infection. It's impossible to tell without testing, and even then we can only test for 2 out of very many viruses. A negative virus test for one of those two doesn't mean negative for other virus.

If a plant is growing and flowering well in good conditions, it doesn't make sense to me as a hobbyist to worry about something I can't detect.

Does anyone know how the heritage plants work?

There are lots of very old plants that have historical significance and may be a hundred or more years old. Many of these plants have viruses and yet are still grown and traded, hopefully with full openess of the condition. Clearly these plants continue to survive and bloom so do people just keep them spearated from unvirused plants? How do they not eventually die? In those cases it must be the 'HIV' situation that MateoinLosAngeles mentioned, right?

As for me, i live in ignorant bliss, and even though i am pretty attached to my 30- 40 plants i dont really worry about viruses. I havent reached the maturity level with most of them to start sharing divisions so perhaps when i do ill get some tests...

I do not test my orchids. It does not make sense for me. My orchids are not valuable or rare, I am not going to do any crosses, I am not planning to sell orchids, I grow orchids to enjoy the flowers and I want collecting plants to be fun and not stressful. If an orchid is healthy and hits all the milestones for growing and blooming...it is either free of virus or resistant to virus and either one is good enough for me. I would rather not be paranoid about virus...I was years ago and it nearly killed my love of growing orchids.

I grow other plants that may or may not have virus and I really value these plants so...it is what it is.

If one notes that all or most of their orchids seem to be failing to thrive and grow and keep having issues with fungus and bacteria and one rules out Calcium deficiency, then one might want to do either some tossing or some testing. But, remember, plant virus is everywhere in our environment...it could be in any plant matter...the fruit and vegetables we buy, the plants outside, trees, nuts, other houseplants, in the mouths of bugs and even on our skin after we have been outside (mosaic virus is easily spread). I sometimes wonder how we can trust it is not in bark or moss used as a medium for plants.

When I had the one Cattleya that I quarantined due to knowing it had been exposed to virus, it missed all the milestones in growth...a complete loss of vigor. It had always put out growths like clockwork twice a year and I saw that the new growths did not begin at the usual time. When it did put out new growths, they grew much more slowly. When it finally bloomed, there was obvious color-break. I was pretty sad but I tossed it.

Just a note...when I added orchids to my plant collection in the 1990's, there were plants that one could use as virus indicator plants. You would nick your plant, take a little sap from it and introduce it to a cut on the indicator plant. The other plant would very quickly begin to express signs of the virus. Funny enough, all those plants are now resistant to virus expression and no longer show any effects so they can no longer be used to test other plants for virus. Some were purposely bred to be resistant and others naturally gained the ability to resist. Maybe orchids will one day also be resistant to virus...maybe some already are.